Support structures including a mast and arm component, such as a typical steel traffic signal supporting structure, are often subject to environmental forces that result in structural degradation and failure. For example, under excitation from wind, as well as traffic-induced drafting effects, traffic signal supporting structures often exhibit large amplitude vibrations that can result in reduced fatigue life of the arm-to-mast connections of these structures. The mechanism of the observed vibrations has been attributed to across-wind effects that lead to galloping of the signal clusters. The corresponding chaotic motion of the structural components leads to persistent stress and strain cycles that result in high cycle fatigue failure, particularly at the arm-to-mast connection. Various types of mitigation devices have been developed. Specifically, numerous devices have been directed to limiting stress cycles by increasing damping. However, it is now recognized that the effectiveness of these mitigation devices has been somewhat limited.